Upset as a result of row and left half abandoned (6)
I believe the answer is:
rankle
'upset' is the definition.
(I've seen this before)
'row and left half abandoned' is the wordplay.
'row' becomes 'rank' (I've seen this in other clues).
'and' says to put letters next to each other.
'left half' means to take half the letters.
'abandoned' becomes 'left' (leave can mean to abandon).
'left' with half the letters taken is 'le'.
'rank'+'le'='RANKLE'
'as a result of' is the link.
(Other definitions for rankle that I've seen before include "Cause continuing irritation" , "Continually vex or irritate" , "Irritate for a long time" , "Annoy continually" , "Nag" .)